ABSTRACT AND APPLIED ANALYSIS, 2012 (SCI-Expanded)
We consider the maximal dissipative second-order difference (or discrete Sturm-Liouville) operators acting in the Hilbert space l(w)(2)(Z) (Z:= {0, +/- 1, +/- 2,...}), that is, the extensions of a minimal symmetric operator with defect index (2,2) in the Weyl-Hamburger limit-circle cases at +/-infinity). We investigate two classes of maximal dissipative operators with separated boundary conditions, called "dissipative at -infinity" and "dissipative at infinity." In each case, we construct a self-adjoint dilation of the maximal dissipative operator and its incoming and outgoing spectral representations, which make it possible to determine the scattering matrix of the dilation. We also establish a functional model of the maximal dissipative operator and determine its characteristic function through the Titchmarsh-Weyl function of the self-adjoint operator. We prove the completeness of the system of eigenvectors and associated vectors of the maximal dissipative operators.